JP2003017904A - Irreversible circuit device and communication unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized irreversible circuit device with less number of components, ease of assembling and high performance and to provide a communication unit. SOLUTION: The irreversible circuit device 1 mainly comprises a metallic case 5, permanent magnets 9, 10 and a center electrode assembly 13. A side face 9d of the permanent magnet 9 is pressed into contact with an inner side face 6a of a side wall 5b of a metallic case 5 and a magnetic pole face 9b is pressed into contact with an inner side face 6c. A side face 10c of the permanent magnet 10 is pressed into contact with an inner side face 6b of a side wall 5b of the metallic case 5, and a magnetic pole face 10a is pressed into contact with an inner side face 6d. A ferrite 20 of the center electrode assembly 13 is placed between the permanent magnets 9, 10 and in the middle of the metallic case 5. The permanent magnets 9, 10 form a DC magnetic field whose line of magnetic force is emitted from a magnetic pole face 9a of the permanent magnet 9 toward a magnetic pole face 10b of the permanent magnet 10. A center line L1 of the permanent magnet 9, a center line L2 of the permanent magnet 10, and a center line L3 of the ferrite 20 are deviated with each other in parallel.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a non-reciprocal circuit device and a communication device.

[0002]

2. Description of the Related Art In general, a lumped-constant isolator used in a mobile communication device such as a mobile phone has a function of passing a signal only in a transmission direction and blocking transmission in the opposite direction. Such a lumped-constant type isolator includes a permanent magnet, a center electrode assembly including ferrite and a plurality of center electrodes arranged on the ferrite, and a metal case that houses the center electrode assembly and the permanent magnet. . In order to improve the electrical performance of this isolator, conventionally, a permanent magnet having a size sufficient to cover ferrite has been used.

However, downsizing of communication devices in recent years,
Along with the reduction in height, it has been considered to make the permanent magnet smaller. Further, in recent years, the frequency of communication devices has been increasing.
In a non-reciprocal circuit device, when it is intended to operate at a high frequency, a high magnetic force must be applied accordingly. However, if the size of the permanent magnet is reduced to reduce the size and height, it becomes difficult to obtain the strength of the magnetic field required to operate at the desired frequency. Further, the magnetic field distribution applied to the ferrite is also deteriorated, and as a result, the characteristics (insertion loss, etc.) are deteriorated. Furthermore, as in the isolator 200 described in Japanese Patent Laid-Open No. 6-260812 shown in FIG.
In the case of the structure in which the side surfaces 209b and 210b on both sides of 09 and 210 are in contact with the metal case 205, respectively, the magnetic pole surfaces 209a and 210a of the permanent magnets 209 and 210 come out from the portions (edge portions) close to the metal case 205. The magnetic force lines are not applied to the ferrite 220 and leak to the metal case 205. This is because the magnetic permeability of the metal case 205 is higher than that of air. As a result, the magnetic field distribution applied to the ferrite becomes worse. Note that FIG.
In the figure, 221 is a wiring board having a plurality of center electrodes on its surface, 212 is a ground plate, and C is a matching capacitor element.

Therefore, in a nonreciprocal circuit device such as an isolator, as shown in FIG. 11, a metal case 235 is used.
Inner side surface 235a and the side surface 23 of the permanent magnets 239, 240.
A structure has been proposed in which the gaps t1 are provided equally between 9b and 240b. At this time, the permanent magnets 239,
The center positions of the magnetic pole surfaces 239a and 240a of 240 and the center position of the center electrode assembly 250 are arranged on a substantially straight line L.

Further, the permanent magnet 239 and the permanent magnet 240
The center electrode assembly 250 is disposed in the center position between the two. From the center position of the center electrode assembly 250 to the permanent magnet 2
The distances to the magnetic pole surfaces 239a and 240a of 39 and 240 are distance d, respectively.

The isolator 231 having the above structure
Is the magnetic pole surfaces 239a, 240 of the permanent magnets 239, 240.
The magnetic lines of force emerging from the edge of a do not leak to the metal case 235, and a DC magnetic field can be efficiently applied to the center electrode assembly 250.

[0007]

However, since the conventional isolator 231 disposes the center positions of the permanent magnets 239 and 240 and the center position of the center electrode assembly 250 on the substantially straight line L, the permanent magnets 239 and 240 are disposed. Side 239 of
The gaps t1 between the b and 240b and the inner surface 235a of the metal case 235 must be evenly spaced.

On the other hand, miniaturization of the isolator 231 itself is progressing, and, for example, the inner dimension W2 of the metal case 235 =
When the length dimension W1 of the permanent magnets 239 and 240 is W1 = 2.0 mm with respect to 2.2 mm, the gap t1 is only 0.1 m.
m. For this reason, when actually assembling the isolator 231, it is very difficult to dispose the permanent magnets 239 and 240 in the metal case 235 with a gap t1 of 0.1 mm left and right accurately. Therefore, the isolator 231
Assembly workability is poor, and the permanent magnets 239, 24
The variation in the arrangement position of 0 is also large. Further, due to this variation, the characteristic variation also increases, and as a result, the non-defective rate of the product also decreases.

In order to solve this problem, Japanese Unexamined Patent Publication No.
Like the isolator described in Japanese Patent No. 308013,
It is conceivable to position the permanent magnet with a resin mold or the like. However, this method has a problem that the number of parts constituting the isolator is increased, the production is troublesome, and the manufacturing cost is increased.

Therefore, an object of the present invention is to provide a non-reciprocal circuit device and a communication device which have a small number of parts, are easy to assemble, and are small in size and high in performance.

[0011]

In order to achieve the above object, the nonreciprocal circuit device according to the present invention comprises: (a) a first permanent magnet having a magnetic pole surface and a side surface substantially perpendicular to the magnetic pole surface. , (B) a second permanent magnet having a magnetic pole surface and a side surface substantially perpendicular to the magnetic pole surface, and (c) disposed between the magnetic pole surface of the first permanent magnet and the magnetic pole surface of the second permanent magnet. , The first
A center electrode assembly composed of a ferrite and a plurality of center electrodes arranged on the ferrite, to which a direct-current magnetic field formed from a permanent magnet toward the second permanent magnet is applied, and (d) two facing electrodes. (E) a side surface of the first permanent magnet and the second permanent magnet, and a metal case having two inner side surfaces and housing the first permanent magnet, the second permanent magnet, and the center electrode assembly. Side faces of the metal case contact one of the two facing inner faces of the metal case, and the center position of the first permanent magnet and the center position of the second permanent magnet respectively correspond to the center electrode assembly. Is different from the center position of. More specifically,
It is characterized in that the side surface of the first permanent magnet and the side surface of the second permanent magnet are in contact with one inner side surface of the two inner side surfaces facing each other of the metal case. Alternatively, it is possible that the side surface of the first permanent magnet is in contact with one inner surface of two opposing inner surfaces of the metal case, and the side surface of the second permanent magnet is in contact with the other inner surface of the metal case. Characterize.

With the above structure, the inner surface of the metal case serves as a reference surface when the first permanent magnet and the second permanent magnet are arranged, and the side surfaces of the first permanent magnet and the second permanent magnet are used as the reference surface. The first permanent magnet and the second permanent magnet can be easily and accurately arranged simply by contacting each other.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a nonreciprocal circuit device and a communication device according to the present invention will be described below with reference to the accompanying drawings. In each embodiment, the same parts and the same parts are designated by the same reference numerals, and duplicated description will be omitted.

[First Embodiment, FIGS. 1 to 6] FIG. 1 is an exploded perspective view showing the structure of an embodiment of a nonreciprocal circuit device according to the present invention. The non-reciprocal circuit device 1 is a lumped constant isolator.

As shown in FIG. 1, the isolator 1 is generally composed of a metal case 5, an internal electric component 8, a circuit board 40 and the like. The internal electric component 8 is generally composed of two permanent magnets 9 and 10, a center electrode assembly 13, matching capacitor elements C1 to C4, a resistance element R, and a ground plate 30.

The metal case 5 includes an upper wall 5a and four side walls 5
b. Here, a pair of inner side surfaces (inner side surfaces in the long side direction) of the four side walls 5b facing each other are designated as 6a and 6b, and another pair of inner side surfaces facing each other are designated as 6c and 6d (see FIG. 2). The metal case 5 is formed by punching and bending a metal plate.

The two permanent magnets 9 and 10 each have a substantially rectangular shape. The permanent magnet 9 has magnetic pole faces 9a, 9
b and side surfaces 9c and 9d perpendicular to the magnetic pole surface 9a. Similarly, the permanent magnet 10 includes the magnetic pole surfaces 10a and 10b and the magnetic pole surface 1
It has side faces 10c and 10d perpendicular to 0b.

The circuit board 40 is a substantially rectangular board.
Three divided through holes 46 are formed on each side surface of the circuit board 40 in the long side direction, and one divided through hole 46 is formed on each side surface of the short side direction. A ground electrode pattern 45, an input electrode pattern 43, and an output electrode pattern 44 are formed on the upper surface 41 of the circuit board 40. And the electrode pattern 4
3 to 45 extend to the lower surface 42 via through holes 46 formed in the side surface of the circuit board 40.

The matching capacitor elements C1 to C4 have connecting capacitor electrodes on the upper and lower surfaces.

The resistance element R has a rectangular parallelepiped shape, and has connection electrodes on its left and right sides. This resistance element R is
The thickness is set to be substantially the same as that of the matching capacitor elements C1 to C4.

The ground plate 30 has a rectangular parallelepiped shape. The ground plate 30 is made of a copper plate or the like and has electrical conductivity. This ground plate 30 is used for the matching capacitor element C1.
The thickness is set to be approximately the same as C4.

The center electrode assembly 13 intersects the substantially rectangular microwave ferrite 20 and two conducting wires (for example, copper wire and silver wire) coated with an insulator so that the intersecting angle becomes approximately 90 degrees. The center electrodes 21 and 22 are formed by winding the ferrite 20 around the surface of the ferrite 20.

The above components are assembled as follows. On the circuit board 40, the matching capacitor elements C1 to C4, the ground plate 30 and the resistance element R are placed,
It is mounted by a method such as soldering. At this time, the connecting capacitor electrodes on the lower surface of the matching capacitor elements C1 and C2 are connected to the ground electrode pattern 45 formed on the upper surface 41 of the circuit board 40, and the connecting capacitor electrode on the lower surface of the matching capacitor element C3 is the upper surface. 41 is electrically connected to the input electrode pattern 43 formed on 41, and the connecting capacitor electrode on the lower surface of the matching capacitor element C4 is electrically connected to the output electrode pattern 44 formed on the upper surface 41 by a method such as soldering. Connecting.

The resistance element R is placed on the non-electrode pattern portion 49 of the circuit board 40. That is, the ground electrode pattern 45 and the resistance element R are in an electrically non-contact state.

Next, the center electrode assembly 13 is placed on the matching capacitor elements C1 to C4, the resistance element R, and the ground plate 30 and mounted by a method such as solder bonding. At this time, one end of the center electrode 21 has a matching capacitor element C1,
It is electrically connected to the connection capacitor electrode on the upper surface of C3 and one terminal electrode of the resistance element R. One end of the center electrode 22 is electrically connected to the connecting capacitor electrodes on the upper surfaces of the matching capacitor elements C2 and C4 and the terminal electrode of the other end of the resistance element R. The other ends of the center electrodes 21 and 22 are the ground plate 30.
Electrically connected to. Accordingly, the center electrode assembly 1
3 is fixed to the elements C1 to C4, R and the ground plate 30.

Next, as shown in FIG. 2, the two permanent magnets 9 and 10 are attached to the inside of the metal case 5, and the metal case 5 is placed on the circuit board 40. At this time, the permanent magnets 9 and 10
Are the inner side surfaces 6a, 6 of the side wall 5b of the metal case 5, respectively.
They are eccentrically arranged with b as a reference plane. That is, the side surface 9d of the permanent magnet 9 is the inner side surface 6a of the side wall 5b of the metal case 5.
And the side surface 10c of the permanent magnet 10 is abutted against the metal case 5
Is abutted on the inner side surface 6b of the side wall 5b. Permanent magnet 9,1
The zero magnetic pole surfaces 9b and 10a are brought into contact with the inner side surfaces 6c and 6d, respectively. Here, for example, the inner dimension W of the metal case 5
2 = 2.2 mm, the length dimension W1 of the permanent magnets 9 and 10 =
It is 2.0 mm.

The ferrite 20 of the center electrode assembly 13 is
It is arranged at the center position between the two permanent magnets 9 and 10 and at positions equidistant from the inner side surfaces 6 a and 6 b of the metal case 5. Therefore, the center line L1 of the permanent magnet 9, the center line L2 of the permanent magnet 10 and the center line L3 of the ferrite 20 are displaced from each other in parallel. The distance from the center position of the center electrode assembly 13 to the magnetic pole surfaces 9a and 10b of the permanent magnets 9 and 10 is the distance d. This ferrite 20
Is applied with a DC magnetic field formed from the magnetic pole surface 9a of the permanent magnet 9 toward the magnetic pole surface 10b of the permanent magnet 10.
Since the elements C1 to C4 and R and the ground plate 30 have substantially the same thickness, the upper surfaces of the elements C1 to C4 and R and the ground plate 30 are substantially parallel to the circuit board 40. Make up. Therefore, the ferrite 20 of the center electrode assembly 13 mounted on the same surface can be arranged substantially perpendicular to the circuit board 40.

Further, the metal case 5 and the ground electrode pattern 45 of the circuit board 40 are joined by soldering. Thus, the isolator 1 as shown in FIG. 3 is formed. FIG. 4 is an electrical equivalent circuit diagram of the isolator 1 shown in FIG.

The permanent magnets 9 and 10 do not necessarily have to be brought into contact with the different inner side surfaces 6a and 6b of the metal case 5, respectively. For example, as shown in FIG. , 10d may be brought into contact with the same inner surface 6a.

In the isolator 1 described above, the inner side surfaces 6a, 6b, 6c and 6d of the metal case 5 serve as reference planes when the permanent magnets 9 and 10 are arranged. That is, the inner surfaces 6a, 6
b is the side surface 9c (or 9d) of the permanent magnet 9 or the permanent magnet 1
The contact reference surface of the 0 side surface 10c (or 10d). Further, the inner side surfaces 6c and 6d serve as contact reference surfaces of the magnetic pole surface 9b of the permanent magnet 9 and the magnetic pole surface 10a of the permanent magnet 10. Therefore, the permanent magnets 9 and 10 can be easily and accurately arranged in the metal case 5. As a result, the permanent magnets 9,
Since there is no variation in the arrangement position of 10, the variation in electrical characteristics is eliminated, and the high-performance isolator 1 is obtained.

Further, since it is not necessary to position the permanent magnets 9 and 10 by resin molding or the like as in the conventional isolator, the isolator 1 having a small number of parts and easy to assemble can be obtained, and its productivity and non-defective products can be obtained. The rate can be improved.

Even if the sizes of the permanent magnets 9 and 10 and the metal case 5 are reduced, the permanent magnets 9 and 10 have the inner side surfaces 6a, 6b, 6c and 6d of the metal case 5 as reference surfaces for contact. Therefore, the permanent magnets 9 and 10 can be easily arranged in the metal case 5.

Further, the permanent magnets 9 and 10 are attached to the metal case 5.
The magnetic field distribution in the metal case 5 can be improved by abutting on the inner side surfaces 6a, 6b and displacing them on the inner side surfaces 6a, 6b side. That is, the lines of magnetic force are the strongest from the edge portions e of the magnetic pole surfaces 9a and 10b of the permanent magnets 9 and 10. The permanent magnets 9 and 10 on the inner surface 6a
By displacing the magnetic field lines to the inner side surface 6b, the edge portion e from which the strongest magnetic force line appears is closer to the ferrite 20 as compared with the conventional isolator 231 shown in FIG. As a result, the ferrite 20 is applied with a strong DC magnetic field from the permanent magnets 9 and 10, and the insertion loss characteristic of the isolator 1 can be improved.

FIG. 6 is a graph in which the insertion loss of various isolators 1 (test samples No1 to No4) in which the arrangement positions of the permanent magnets 9 and 10 are changed are measured. For comparison, FIG.
The insertion loss of the conventional isolator 231 (test sample No. 5) shown in FIG. Specimen No. in which the permanent magnets 9 and 10 were brought into contact with different inner surfaces 6a and 6b, respectively
The insertion loss of the isolator 1 of Nos. 1 and 2 is about 0.
It is improved by 2 dB. Further, the test bodies No. 3 and 4 in which the permanent magnets 9 and 10 were brought into contact with the same inner surface 6a (or 6b)
The insertion loss of the isolator 1 is about 0.1 to 10 times that of the conventional isolator 231 of the test body No5.
It is improved by 0.15 dB.

[Second Embodiment, FIGS. 7 and 8] As shown in FIG. 7, in the second embodiment, instead of the matching capacitor elements C1 to C4, the resistor element R and the circuit board 40,
LTCC (Low
Temperature Cofired Cera
mic) shows an isolator 2 using a multilayer substrate 50.

On the upper surface of the LTCC multilayer substrate 50, a grounding electrode pattern 45 and connecting electrode patterns 51 and 52 are formed. An input external electrode pattern 53, an output external electrode pattern 54, and a ground external electrode pattern 55 each having a through hole 46 divided into two are provided on the edge of the TLCC multilayer substrate 50. The connection electrode patterns 51 and 52 are connected to one ends of the center electrodes 21 and 22, and the ground electrode pattern 45 is connected to the center electrode 21 and
It is connected to the other end of 22.

Here, the LTCC multilayer substrate 50 is formed by laminating layers made of a low temperature sintered material or a low temperature fired ceramic with an internal conductor film and an internal resistance film interposed therebetween. Further, a via hole is formed in a specific layer, and is electrically connected to an internal conductor film or an internal resistance film inside the LTCC multilayer substrate 50, and the resistor element R and the matching capacitor elements C1 to C4 are connected to the via hole. Forming an electric circuit that

As shown in FIG. 8, in the isolator 2, the center electrode assembly 13 is placed on the multilayer substrate 50. The permanent magnet 9 and the permanent magnet 10 are the same as the isolator 1 of FIG.
It is abutted on and affixed to b.

The above isolator 2 has the same operational effect as the first embodiment. Furthermore, since the matching capacitor elements C1 to C4 and the resistance element R are formed in the LTCC multilayer substrate 50, the solder joint portions can be reduced as compared with the isolator 1, and the isolator 2 can be used.
The production cost can be reduced.

[Third Embodiment, FIG. 9] In the present third embodiment, an embodiment of a communication device will be described taking a mobile phone as an example.

FIG. 9 is an electric circuit block diagram of the RF portion of the mobile phone 120. In FIG. 9, 122 is an antenna element, 123 is a duplexer, 124 and 126 are transmission side power amplifiers, 125 is a transmission side interstage band pass filter, 127 is a transmission side mixer, 128 is a reception side low noise amplifier, and 129 is reception. Bandpass filter for side stage, 130
Is a receiving side mixer, 131 is an isolator, 132 is a voltage controlled oscillator (VCO), and 133 is a local band pass filter.

Here, as the isolator 131, the isolators 1 and 2 of the first and second embodiments can be used. By mounting the isolators 1 and 2, it is possible to realize a high-performance mobile phone at low cost.

[Other Embodiments] The present invention is not limited to the above embodiments, but can be modified into various configurations within the scope of the present invention. For example, the center electrode 2
The conductors 1 and 22 are not limited to those having a conductive wire (having a substantially circular cross section), and may be those having a metal foil (having a flat cross section). Further, the shape of the center electrode assembly 13 is not limited to a rectangular shape, but may be a columnar shape, a deformed angular shape, or the like. The permanent magnets 9 and 10 may have any shape as long as the side surface of the permanent magnet can contact the inner side surface of the metal case. For example, the permanent magnets 9 and 10 may have a rectangular shape with rounded corners, a circular shape, or a deformed angular shape. Good.

In addition to the isolator, the present invention can be applied to various non-reciprocal circuit devices such as circulators.

[0045]

As is apparent from the above description, according to the present invention, the side surface of the first permanent magnet and the side surface of the second permanent magnet are respectively the inner surface of one of the two inner surfaces facing each other. The first permanent magnet and the second permanent magnet.
The permanent magnet can be easily positioned on the inner surface of the metal case. Therefore, it is possible to obtain a non-reciprocal circuit device and a communication device that are easily assembled.

Furthermore, since the first permanent magnet and the second permanent magnet are brought into contact with the inner side surface of the metal case and are arranged offset to the inner side surface side, the magnetic field distribution in the metal case can be improved. The insertion loss characteristics of the non-reciprocal circuit device and the communication device can be improved.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a first embodiment of a non-reciprocal circuit device according to the present invention.

FIG. 2 is a schematic plan view showing an arrangement relationship between a metal case, a permanent magnet and a ferrite of the nonreciprocal circuit device shown in FIG.

FIG. 3 is a perspective view of the nonreciprocal circuit device shown in FIG. 1 after completion of assembly.

FIG. 4 is an electrical equivalent circuit diagram of the nonreciprocal circuit device shown in FIG.

5 shows a modification of the non-reciprocal circuit device shown in FIG.
FIG. 3 is a schematic plan view showing a positional relationship between a metal case, a permanent magnet and ferrite.

FIG. 6 is a graph showing the relationship between the non-reciprocal circuit device shown in FIGS. 1, 5 and 11 and the insertion loss.

FIG. 7 is an exploded perspective view of a second embodiment of a non-reciprocal circuit device according to the present invention.

8 is a schematic plan view showing an arrangement relationship between a metal case, a permanent magnet and a ferrite of the nonreciprocal circuit device shown in FIG.

FIG. 9 is a block diagram showing an embodiment of a communication device according to the present invention.

FIG. 10 is a vertical sectional view showing an embodiment of a conventional non-reciprocal circuit device.

FIG. 11 is a schematic plan view showing a positional relationship between a metal case of another conventional non-reciprocal circuit device, a permanent magnet, and a ferrite.

[Explanation of symbols] 1, 2 ... Isolator (non-reciprocal circuit element) 5 ... Metal case 5b ... Side wall of metal case 6a, 6b ... Inside surface of metal case 9, 10 ... Permanent magnet 9a, 9b, 10a, 10b ... Magnetic pole surface of permanent magnet 9c, 9d, 10c, 10d ... Side surface of permanent magnet 13 ... Center electrode assembly 20 ... Microwave ferrite 21, 22 ... Center electrode 120 ... Mobile phone (communication device)

Claims (4)

[Claims] 1. A first permanent magnet having a magnetic pole surface and a side surface substantially perpendicular to the magnetic pole surface, a second permanent magnet having a magnetic pole surface and a side surface substantially perpendicular to the magnetic pole surface, and the first permanent magnet. Disposed between the magnetic pole surface of the first permanent magnet and the magnetic pole surface of the second permanent magnet, and a DC magnetic field formed from the first permanent magnet toward the second permanent magnet is applied to the ferrite and the ferrite. A center electrode assembly composed of a plurality of center electrodes, and a metal case having two inner surfaces facing each other and accommodating the first permanent magnet, the second permanent magnet, and the center electrode assembly. And a side surface of the first permanent magnet and a side surface of the second permanent magnet are in contact with one of inner surfaces of two opposing inner surfaces of the metal case, respectively, and a center position of the first permanent magnet and The center position of the second permanent magnet is Nonreciprocal circuit device, characterized in that, that differ from the central position of the center electrode assembly. 2. The side surface of the first permanent magnet and the side surface of the second permanent magnet are in contact with one inner side surface of two inner side surfaces facing each other of the metal case. The nonreciprocal circuit device described in 1. 3. A side surface of the first permanent magnet abuts one inner side surface of two opposing inner side surfaces of the metal case, and a side surface of the second permanent magnet is the other inner side surface of the metal case. The non-reciprocal circuit device according to claim 1, wherein the non-reciprocal circuit device is in contact with. 4. A communication device comprising the nonreciprocal circuit element according to claim 1. Description: